<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script src="https://unpkg.com/vue@next"></script>
<div id="app">
    <todo-item></todo-item>
    <todo-item></todo-item>
    <todo-item></todo-item>
</div>
<script>
    const vueOpt = {
        data() {
            return {}
        }
    }

    const app = Vue.createApp(vueOpt)
    app.component('todo-item', {
        data() {
            return {
                count: 5
            }
        },
        template: `
            <button @click="count++">点我，点我</button><span>count:{{count}}</span>
        `
    })
    app.mount('#app');
</script>
</body>
</html>
